JP6337831B2 - Water heater - Google Patents

Description

  The present invention relates to a water heater.

  A hot water heater is known that has a hot water supply heat exchanger that exchanges heat between a heat storage fluid supplied from a heat storage tank and water supply supplied from a water source, and heats the water supply with the heat of the heat storage fluid. (For example, refer to Patent Document 1). In the water heater disclosed in Patent Document 1 below, the temperature of the hot water flowing out of the hot water heat exchanger is detected by a temperature sensor, and based on the difference between the detected temperature and the hot water target temperature (target temperature), Control the circulation flow rate.

JP-A-5-99507

  However, in the water heater of Patent Document 1, a manufacturing cost tends to be increased by requiring a temperature sensor that detects the temperature of hot water flowing out of the hot water heat exchanger.

  The present invention has been made to solve the above-described problems, and includes a hot water supply heat exchanger that exchanges heat between a heat storage fluid supplied from a heat storage tank and water supplied from a water source. Another object of the present invention is to suppress a deviation between the temperature of hot water flowing out from the hot water supply heat exchanger and its target temperature with a simple configuration.

  The water heater according to the present invention exchanges heat between a heat storage tank that stores a heat storage fluid, a heating unit that heats the heat storage fluid, a heat storage fluid supplied from the heat storage tank, and a water supply supplied from a water source. A hot water supply heat exchanger for heating the hot water, a fluid pump for supplying the heat storage fluid to the hot water heat exchanger, a hot water flow rate sensor for detecting the flow rate of the hot water, and a heat storage fluid supplied to the hot water heat exchanger. From the pump control means for controlling the fluid pump so that the flow rate matches the target flow rate determined according to the flow rate of the feed water, the temperature of the heat storage fluid supplied to the hot water heat exchanger, and the hot water heat exchanger Based on the storage means for storing information on the heat exchange loss value, which is the difference from the temperature of the water supply flowing out, and the temperature obtained by adding the heat exchange loss value to the target temperature of the water supply flowing out of the hot water supply heat exchanger The temperature of the heat storage fluid stored in the tank Those having a thermal temperature control means.

  According to the present invention, in a hot water supply apparatus having a hot water supply heat exchanger that exchanges heat between a heat storage fluid supplied from a heat storage tank and water supply supplied from a water source, the heat flows out from the hot water supply heat exchanger. It is possible to suppress the difference between the hot water temperature and the target temperature with a simple configuration.

It is a block diagram which shows the water heater of Embodiment 1 of this invention. It is a figure which shows an example of the relationship between a heat exchange loss value and a hot water supply flow rate. It is a block diagram of the control apparatus with which the water heater of Embodiment 1 of this invention is provided. It is a hardware block diagram of the control apparatus with which the water heater of Embodiment 1 of this invention is provided. It is a block diagram of the control apparatus with which the water heater of Embodiment 2 of this invention is provided. It is a flowchart of the routine performed by the control apparatus in Embodiment 2 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. Elements common to the drawings are denoted by the same reference numerals, and redundant description is simplified or omitted. Note that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the spirit of the present invention. In principle, the number, arrangement, orientation, shape, and size of the devices, instruments, and components in the present invention are not limited to the number, arrangement, orientation, shape, and size shown in the drawings. Further, the present invention includes all combinations of configurations that can be combined among the configurations described in the following embodiments. In the present specification, “water” is a concept including liquid water of all temperatures from low-temperature cold water to high-temperature hot water.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram illustrating a water heater according to Embodiment 1 of the present invention. As shown in FIG. 1, the water heater 35 according to the first embodiment includes a tank unit 33 that incorporates a hot water storage tank 8, an HP (heat pump) unit 7, and a control device 100. The HP unit 7 and the tank unit 33 are connected to each other via an HP forward pipe 14, an HP return pipe 15, and electrical wiring (not shown). The hot water supply device 35 of the first embodiment is a hot water storage type hot water supply device including the hot water storage tank 8 as a heat storage tank.

  Various valves, pumps, actuators such as a compressor, and various sensors included in the tank unit 33 and the HP unit 7 are electrically connected to the control device 100. A remote controller 44 arranged outside the water heater 35 is connected to the control device 100 so as to be capable of two-way communication. Although not shown, the remote controller 44 includes a display unit that displays information such as the state of the water heater 35, an operation unit such as a switch that is operated by the user, and the like. The user operates the remote controller 44 to change the operation command and set value for the water heater 35. The control device 100 controls the operation of the water heater 35 by operating each actuator based on information detected by each sensor and information received from the remote controller 44.

  In the present embodiment, the control device 100 is built in the tank unit 33. Not only such a configuration but also a control device may be incorporated in the HP unit 7. Alternatively, the control device built in the tank unit 33 and the control device built in the HP unit 7 may be controlled in cooperation.

  The HP unit 7 is an example of a heating unit that heats the heat storage fluid. The heat storage fluid in the present embodiment is water. The HP unit 7 heats water supplied from the tank unit 33. The HP unit 7 includes a refrigerant circuit in which the compressor 1, the water-refrigerant heat exchanger 3, the expansion valve 4, and the evaporator 6 are annularly connected by a refrigerant pipe 5. The water-refrigerant heat exchanger 3 heats water with the heat of the refrigerant heated by the compressor 1.

  The hot water storage tank 8 stores water as a heat storage fluid. The heat storage fluid in the present invention may be a liquid heat medium other than water. Inside the hot water storage tank 8, a temperature stratification can be formed in which the upper side is hot and the lower side is low due to the difference in density of the heat storage fluid depending on the temperature. The first water supply pipe 9a is connected to a water source such as a water supply. A water inlet 8a provided in the lower part of the hot water storage tank 8 is connected to the first water supply pipe 9a via a third water supply pipe 9c. Water supplied from the water source is introduced into the hot water storage tank 8 through the first water supply pipe 9a and the third water supply pipe 9c. The hot water storage tank 8 is maintained in a full water state. A pressure reducing valve 31 is provided in the middle of the third water supply pipe 9c. The water pressure of the water source is adjusted to a specified pressure by the pressure reducing valve 31 and then acts in the hot water storage tank 8.

  One end of a water outlet pipe 10 is connected to a water outlet 8 b provided in the lower part of the hot water storage tank 8. The other end of the water outlet pipe 10 is connected to the suction side of the water pump 12. The discharge side of the water pump 12 is connected to the inlet of the HP unit 7 via the HP forward pipe 14. A three-way valve 18 is built in the tank unit 33. The three-way valve 18 is a flow path switching means having one inlet (a port) and two outlets (b port and c port). The a port of the three-way valve 18 is connected to the outlet of the HP unit 7 via the HP return pipe 15. The b port of the three-way valve 18 is connected via a hot water supply pipe 13 to a hot water inlet 8 d provided at the upper part of the hot water storage tank 8. The c port of the three-way valve 18 is connected via a bypass pipe 16 to a hot water inlet 8 c provided between the central part and the lower part of the hot water storage tank 8.

  Hot water heated using the HP unit 7 flows into the hot water storage tank 8 from the hot water inlet 8d through the HP return pipe 15 and the hot water supply pipe 13, and low temperature water flows through the third water supply pipe 9c to the water inlet 8a. Inflow from. Thereby, hot water is stored in the hot water storage tank 8 so that a temperature difference is generated between the upper and lower sides. A plurality of hot water storage temperature sensors are attached to the surface of the hot water storage tank 8 at different heights. In the illustrated configuration, a hot water storage temperature sensor 42 is attached to the upper part of the surface of the hot water storage tank 8, and a hot water storage temperature sensor 43 is attached to the lower part of the surface of the hot water storage tank 8. By detecting the vertical temperature distribution in the hot water storage tank 8 with these hot water storage temperature sensors 42, 43, the remaining hot water amount and the heat storage amount in the hot water storage tank 8 can be grasped. The control device 100 controls the start and stop of the heat storage operation based on the remaining hot water amount or the heat storage amount. Not only the illustrated configuration but also three or more hot water storage temperature sensors may be provided.

  The tank unit 33 incorporates a hot water supply heat exchanger 52. The hot water supply heat exchanger 52 is a heat exchanger that heats water by exchanging heat between the heat storage fluid (high temperature water) supplied from the hot water storage tank 8 and the water supplied from the water source. The secondary inlet of the hot water supply heat exchanger 52 is connected to the first water supply pipe 9a through the second water supply pipe 9b. The secondary outlet of the hot water supply heat exchanger 52 is connected to the hot water tap 34 via the hot water supply pipe 21. In the following description, water supplied from the water source to the hot water supply heat exchanger 52 through the first water supply pipe 9a and the second water supply pipe 9b is referred to as “water supply”. If it is this Embodiment, the hot water produced | generated by heating feed water with the hot water supply heat exchanger 52 can be supplied to the hot-water tap 34. According to this embodiment, the water pressure of the water source can be applied to the hot water tap 34 without reducing the pressure by the pressure reducing valve 31. For this reason, hot water can be supplied to the hot-water tap 34 at high pressure.

  The hot water supply flow rate sensor 49 detects the flow rate of the hot water supplied to the hot water supply heat exchanger 52. In the present embodiment, a hot water supply flow rate sensor 49 is arranged in the middle of the second water supply pipe 9b. In the following description, the flow rate of hot water detected by the hot water flow rate sensor 49 is referred to as “hot water flow rate”.

  A primary inlet of the hot water supply heat exchanger 52 is connected to a hot water outlet 8e provided in the upper part of the hot water storage tank 8 via a heat source introduction pipe 46a. The primary outlet of the hot water supply heat exchanger 52 is connected to a hot water inlet 8f provided at the lower part of the hot water storage tank 8 via a heat source outlet pipe 46b. In the following description, the hot water in the hot water storage tank 8 led out from the hot water lead-out port 8e is again supplied from the hot water introduction port 8f via the heat source introduction pipe 46a, the hot water supply heat exchanger 52, and the heat source lead-out pipe 46b. The circuit that returns to 8 is referred to as a heat source circuit 46. In order to make the distinction from the water supply easy to understand, the hot water flowing through the heat source circuit 46 and the hot water stored in the hot water storage tank 8 are referred to as a heat storage fluid.

  A fluid pump 48 for supplying a heat storage fluid to the hot water supply heat exchanger 52 is disposed in the middle of the heat source outlet pipe 46b. A heat source side flow rate sensor 50 that detects the flow rate of the heat storage fluid supplied to the hot water supply heat exchanger 52 is disposed in the middle of the heat source outlet pipe 46b. In the following description, the flow rate of the heat storage fluid detected by the heat source side flow rate sensor 50 is referred to as “heat source side flow rate”.

  A hot water supply pipe connected to the mixed water tap 51 such as a faucet outside the hot water heater 35 is connected to the hot water tap 34. The mixed water tap 51 is an example of a hot water supply terminal. A water supply pipe 9 d that supplies low-temperature water as a water source and a hot water discharge pipe 53 are further connected to the mixing tap 51. The mixing tap 51 mixes hot water supplied from the hot water tap 34 of the hot water supply machine 35 with low-temperature water supplied from the water supply pipe 9 d, and discharges the mixed hot water from the hot water outlet pipe 53. The user can adjust the temperature of hot water discharged from the hot water discharge pipe 53 by adjusting the mixing ratio of the mixing tap 51.

  Next, the heat storage operation of the water heater 35 of the present embodiment will be described. The heat storage operation is an operation of storing heat in the hot water storage tank 8 by storing the heat storage fluid heated by operating the HP unit 7 in the hot water storage tank 8. During the heat storage operation, the three-way valve 18 is controlled so that the a port and the b port communicate with each other and the c port is closed. As a result, the HP return pipe 15 and the hot water supply pipe 13 communicate with each other, and the flow path to the hot water inlet 8c of the hot water storage tank 8 is shut off by closing the bypass pipe 16 side.

  In the heat storage operation, the control device 100 operates the water pump 12 and the HP unit 7 with the three-way valve 18 being controlled as described above. In the heat storage operation, it is as follows. A low-temperature heat storage fluid flowing out from the water outlet 8 b of the hot water storage tank 8 is guided to the HP unit 7 via the water outlet pipe 10, the water pump 12 and the HP forward pipe 14, and heated in the water-refrigerant heat exchanger 3. Is done. The heat storage fluid heated to a high temperature flows into the hot water storage tank 8 from the hot water inlet 8d via the HP return pipe 15, the three-way valve 18 and the hot water supply pipe 13, and is stored therein. By executing such a heat storage operation, the hot storage fluid is stored from the upper layer inside the hot water storage tank 8, and the layer of the high temperature storage fluid gradually becomes thicker.

  A heating temperature sensor 17 that detects the temperature of the heat storage fluid after being heated by the HP unit 7 is attached to the HP return pipe 15. The temperature of the heat storage fluid after being heated by the HP unit 7 is hereinafter referred to as “heating temperature”. During the heat storage operation, the control device 100 performs control so that the heating temperature matches the target value of the heating temperature. The target value of the heating temperature is hereinafter referred to as “heating target temperature”. For example, the control device 100 controls the water pump 12 so that the heating temperature detected by the heating temperature sensor 17 matches the heating target temperature. When the heating temperature is higher than the heating target temperature, the control device 100 reduces the heating temperature by correcting the output of the water pump 12 so that the flow rate delivered by the water pump 12 increases. When the heating temperature detected by the heating temperature sensor 17 is lower than the heating target temperature, the control device 100 corrects the output of the water pump 12 so that the flow rate delivered by the water pump 12 is reduced, thereby increasing the heating temperature. To raise.

  Next, a hot water supply operation of the water heater 35 of the present embodiment will be described. The hot water supply operation is an operation in which hot water generated by heating the hot water with the hot water supply heat exchanger 52 is supplied to the hot water tap 34. When the user opens the mixed water tap 51, the water supply flows into the hot water supply heat exchanger 52. When the hot water supply flow rate sensor 49 detects that the water supply has flowed into the hot water supply heat exchanger 52, the control device 100 starts the hot water supply operation by operating the fluid pump 48. In hot water operation, it is as follows. The high-temperature heat storage fluid stored in the hot water storage tank 8 is introduced to the primary side of the hot water supply heat exchanger 52 through the hot water outlet 8e and the heat source introduction pipe 46a by the operation of the fluid pump 48. Water supplied from the second water supply pipe 9b is introduced to the secondary side of the hot water supply heat exchanger 52 by the pressure of the water source. The water supply is heated by heat exchange with the heat storage fluid on the primary side in the hot water supply heat exchanger 52. This hot water is supplied to the hot water tap 34 via the hot water supply pipe 21.

  In the following description, the temperature of the hot water flowing out from the hot water supply heat exchanger 52 in the hot water supply operation (that is, the temperature of hot water supplied to the hot water tap 34) is referred to as “hot water temperature”. Further, the temperature of the heat storage fluid supplied from the hot water storage tank 8 to the hot water supply heat exchanger 52 in the hot water supply operation is referred to as “heat source temperature”. The hot water supply temperature is somewhat lower than the heat source temperature. The difference between the heat source temperature and the hot water supply temperature is hereinafter referred to as “heat exchange loss value”. The heat exchange loss value depends on the heat source temperature, the heat transfer performance of the hot water supply heat exchanger 52, and the hot water supply flow rate.

  FIG. 2 is a diagram illustrating an example of the relationship between the heat exchange loss value and the hot water supply flow rate. As shown in FIG. 2, the heat exchange loss value increases as the hot water supply flow rate increases. In the example shown in FIG. 2, the heat exchange loss value when the hot water supply flow rate is 2 L / min is about 2 degrees. In this case, assuming that the heat source temperature is 50 ° C., the hot water supply temperature is about 48 ° C. by subtracting about 2 degrees from 50 ° C. In the example shown in FIG. 2, the heat exchange loss value when the hot water supply flow rate is 10 L / min is about 7 degrees. In this case, assuming that the heat source temperature is 50 ° C., the hot water supply temperature is about 43 ° C. by subtracting about 7 degrees from 50 ° C.

  FIG. 3 is a block diagram of the control device 100 provided in the water heater 35 of the first embodiment. As shown in FIG. 3, the control device 100 includes a pump control unit 101, a storage unit 102, and a heat storage temperature control unit 103. FIG. 4 is a hardware configuration diagram of the control device 100 provided in the water heater 35 according to the first embodiment. The control device 100 includes a processor 1000 and a memory 1001. The function of the control device 100 is achieved by the processor 1000 executing a program stored in the memory 1001. The control device 100 may include a plurality of processors. The control device 100 may include a plurality of memories. A plurality of processors and a plurality of memories may cooperate to achieve the function of the control device 100.

  During the hot water supply operation, the pump control unit 101 of the control device 100 determines the target flow rate of the heat storage fluid supplied to the hot water supply heat exchanger 52 according to the hot water supply flow rate detected by the hot water supply flow rate sensor 49. The pump control unit 101 controls the fluid pump 48 so that the heat source side flow rate detected by the heat source side flow rate sensor 50 matches the target flow rate. For example, the pump control unit 101 performs feedback control that gives a control signal to the fluid pump 48 based on a deviation between the heat source side flow rate detected by the heat source side flow rate sensor 50 and the target flow rate. The pump control unit 101 generates a control signal to the fluid pump 48 by, for example, PID (Proportional Integral Derivative) control.

  The target flow rate may be set to a value equal to the hot water supply flow rate, for example. Alternatively, the target flow rate may be a value obtained by multiplying the hot water supply flow rate by a predetermined coefficient, for example.

  If it is this Embodiment, the following effects are acquired by controlling so that the heat source side flow volume may correspond to the target flow volume determined according to the hot water supply flow volume. Since frequent fluctuation (hunting) of the heat source side flow rate can be reliably suppressed, frequent fluctuation (hunting) of the heating amount in the hot water supply heat exchanger 52 can be reliably suppressed. Therefore, frequent fluctuations (hunting) of the hot water supply temperature can be reliably suppressed, so that user discomfort can be reliably suppressed.

  The target value of the hot water supply temperature is hereinafter referred to as “hot water supply target temperature”. The user can change the target hot water supply temperature by operating the remote controller 44. Control device 100 receives information on the hot water supply target temperature from remote controller 44.

  The storage unit 102 of the control device 100 stores information related to the heat exchange loss value in advance. The heat storage temperature control unit 103 of the control device 100 controls the temperature of the heat storage fluid stored in the hot water storage tank 8 based on the temperature obtained by adding the heat exchange loss value to the hot water supply target temperature. For example, the heat storage temperature control unit 103 sets a value equal to the temperature obtained by adding the heat exchange loss value to the hot water supply target temperature as the heating target temperature, and performs the heat storage operation. By performing the heat storage operation, the heat storage fluid having a temperature equal to the temperature obtained by adding the heat exchange loss value to the hot water supply target temperature is stored in the hot water storage tank 8. That is, the heat storage fluid having a higher temperature than the target hot water supply temperature is stored in the hot water storage tank 8 by the heat exchange loss value. In the hot water supply operation, the actual hot water supply temperature is close to the hot water supply target temperature by supplying the heat storage fluid at the temperature to the hot water supply heat exchanger 52. The heat storage temperature control unit 103 may perform the heat storage operation by setting, for example, a value obtained by correcting the temperature obtained by adding the heat exchange loss value to the hot water supply target temperature upward or downward as the heating target temperature.

  According to the present embodiment, the actual hot water supply temperature can be made close to the hot water supply target temperature without detecting the actual hot water supply temperature. If it is this Embodiment, the temperature sensor which detects actual hot water supply temperature is unnecessary, and manufacturing cost is low. If it is this Embodiment, the shift | offset | difference of actual hot water supply temperature and hot water supply target temperature can be suppressed with a simple structure.

  If it is this Embodiment, the following effects are acquired by controlling so that the heat source side flow volume may correspond to the target flow volume determined according to the hot water supply flow volume. Since the heat source side flow rate is uniquely determined according to the hot water supply flow rate, the heat exchange loss value can be apparently independent of the heat source side flow rate. For this reason, by controlling the temperature of the heat storage fluid stored in the hot water storage tank 8 as described above, the actual hot water supply temperature can be made close to the hot water supply target temperature. On the other hand, assuming that the heat source side flow rate is controlled independently of the hot water supply flow rate and the heat source side flow rate is not uniquely determined according to the hot water supply flow rate, the heat exchange loss value changes as the heat source side flow rate changes. Therefore, it becomes difficult to make the actual hot water supply temperature close to the hot water supply target temperature.

  In the present embodiment, storage unit 102 stores a heat exchange loss value at a preset reference hot water supply flow rate. By applying the value of the reference hot water supply flow rate to the relationship between the heat exchange loss value and the hot water supply flow rate as illustrated in FIG. 2, the heat exchange loss value at the reference hot water supply flow rate is determined. The heat storage temperature control unit 103 controls the temperature of the heat storage fluid stored in the hot water storage tank 8 based on the temperature stored in the storage unit 102 and the heat exchange loss value at the reference hot water supply flow rate added to the hot water supply target temperature. The heat exchange loss value changes according to the hot water supply flow rate. For this reason, in the present embodiment, in the hot water supply operation, when the actual hot water supply flow rate does not match the reference hot water supply flow rate, the actual hot water supply temperature supplied to the hot water tap 34 does not exactly match the hot water supply target temperature. For example, when the actual hot water supply flow rate is higher than the reference hot water supply flow rate, the actual hot water supply temperature is slightly lower than the target hot water supply temperature. Conversely, when the actual hot water supply flow rate is lower than the reference hot water supply flow rate, the actual hot water supply temperature is slightly higher than the hot water supply target temperature. The user can adjust the temperature of hot water discharged from the hot water discharge pipe 53 by adjusting the mixing ratio of the mixing tap 51. For this reason, if the actual hot water supply temperature is close to the hot water supply target temperature, there is no problem even if the actual hot water supply temperature does not exactly match the hot water supply target temperature.

  The user discomfort that may occur when the actual hot water supply temperature is lower than the hot water supply target temperature is relatively small. In contrast, user discomfort that may occur when the actual hot water temperature is higher than the target hot water temperature is relatively large. For this reason, it is desirable to make it difficult for the actual hot water supply temperature to become higher than the hot water supply target temperature. In this Embodiment, the heat exchange loss value memorize | stored in the memory | storage part 102 becomes small, so that the setting of the reference | standard hot water supply flow rate is made low. The smaller the heat exchange loss value, the lower the temperature of the heat storage fluid stored in the hot water storage tank 8, so that the actual hot water supply temperature is less likely to become higher than the hot water supply target temperature.

  In view of the above-described matters, in the present embodiment, it is desirable to set the reference hot water supply flow rate to a low value. For example, it is desirable to set the reference hot water supply flow rate to the assumed minimum hot water supply flow rate. Here, the “assumed minimum hot-water supply flow rate” refers to the minimum hot-water supply flow rate under use conditions in which the hot-water supply flow rate is stable for a certain time or more. For example, the hot water supply flow rate in a state where the hot water supply flow rate becomes unstable as at the start and stop of the hot water supply from the mixed tap 51 is not included in the “assumed minimum hot water supply flow rate”. As an example, it is assumed that the “assumed minimum hot water flow rate” is 2 L / min, and the heat exchange loss value is 2 degrees when the hot water flow rate is 2 L / min. In the case of this example, “2 degrees” is stored in advance in the storage unit 102 as a heat exchange loss value. By doing in this way, since it can suppress reliably that actual hot water supply temperature becomes higher than hot water supply target temperature, it can suppress reliably that a user's discomfort becomes large.

  When the actual hot water flow rate detected by the hot water flow rate sensor 49 is less than the “assumed minimum hot water flow rate”, the control device 100 does not operate the fluid pump 48 and does not perform the hot water supply operation. Also good. By doing so, since it can suppress more reliably that actual hot water supply temperature becomes higher than hot water supply target temperature, it can suppress more reliably that a user's discomfort becomes large.

  The storage unit 102 may store the relationship between the heat exchange loss value and the hot water supply flow rate as illustrated in FIG. The memory | storage part 102 may memorize | store the relationship between a heat exchange loss value and a hot_water | molten_metal supply flow volume as a search table, for example, or may memorize | store it as an approximate expression. Control device 100 may learn the actual hot water flow rate detected by hot water flow rate sensor 49. Control device 100 may determine a reference hot water supply flow rate based on the learned information. For example, control device 100 may determine the reference hot water supply flow rate based on a value obtained by statistically processing the learned actual hot water supply flow rate. The statistically processed values are, for example, an average value, median value, total value, maximum value, minimum value, mode value, variance, standard deviation, and the like. The heat storage temperature control unit 103 uses the heat exchange loss value obtained by applying the reference hot water supply flow rate determined in this way to the relationship between the heat exchange loss value and the hot water supply flow rate stored in the storage unit 102. You may control.

Embodiment 2. FIG.
Next, the second embodiment of the present invention will be described with reference to FIG. 5 and FIG. 6. The description will focus on the differences from the first embodiment described above, and the same parts or corresponding parts will have the same names. The description will be simplified or omitted.

  FIG. 5 is a block diagram of the control device 100 provided in the water heater 35 of the second embodiment. As shown in FIG. 5, the control device 100 according to the second embodiment further includes a recording unit 104 in addition to the pump control unit 101, the storage unit 102, and the heat storage temperature control unit 103. Other configurations of the water heater 35 of the second embodiment are the same as those of the first embodiment.

  The recording unit 104 of the control device 100 records the minimum hot water supply flow rate when the hot water supply flow rate is stabilized based on information detected by the hot water supply flow rate sensor 49 during the hot water supply operation. Here, the “minimum hot water supply flow rate” refers to the minimum hot water supply flow rate under use conditions in which the hot water supply flow rate is stable for a certain time or more. For example, the hot water supply flow rate in a state where the hot water supply flow rate becomes unstable, such as at the start and stop of hot water from the mixed tap 51, is not included in the “minimum hot water supply flow rate”.

  The storage unit 102 stores the relationship between the heat exchange loss value and the hot water supply flow rate as illustrated in FIG. The heat storage temperature control unit 103 obtains the heat exchange loss value by applying the minimum hot water supply flow rate recorded by the recording unit 104 to the relationship between the heat exchange loss value and the hot water supply flow rate stored in the storage unit 102. The heat storage temperature control unit 103 controls the temperature of the heat storage fluid stored in the hot water storage tank 8 based on the temperature obtained by adding the heat exchange loss value to the hot water supply target temperature.

  If it is this Embodiment, the recording part 104 can grasp | ascertain the minimum hot-water supply flow rate according to an actual use condition by recording the minimum hot-water supply flow rate. In the present embodiment, the heat storage temperature control unit 103 controls the temperature of the heat storage fluid stored in the hot water storage tank 8 using the heat exchange loss value at the minimum hot water supply flow rate according to the actual use situation. By doing so, the following effects can be obtained. Since it can suppress reliably that an actual hot water supply temperature becomes higher than hot water supply target temperature, it can suppress reliably that a user's discomfort becomes large. The minimum hot water flow rate recorded by the recording unit 104 is hereinafter referred to as “minimum hot water flow rate”.

  FIG. 6 is a flowchart of a routine executed by control device 100 in the second embodiment. The control device 100 periodically and repeatedly executes the routine shown in FIG. In step S <b> 1 of FIG. 6, the control device 100 determines the presence or absence of the flow of water supply based on the detection signal of the hot water supply flow rate sensor 49. When it is determined that there is no flow of water supply, the control device 100 proceeds from step S1 to step S2. In step S <b> 2, the control device 100 determines that the mixing faucet 51 is closed, stops the fluid pump 48, and stops the supply of the heat storage fluid to the hot water supply heat exchanger 52.

  When control device 100 determines that there is a flow of water supply, control device 100 proceeds from step S1 to step S4. In step S4, the control device 100 determines that the mixing faucet 51 is open, and performs a hot water supply operation. That is, in step S4, the fluid pump 48 is operated to supply the heat storage fluid to the hot water supply heat exchanger 52. In step S4, the pump control unit 101 controls the fluid pump 48 to control the heat source side flow rate as described above.

  The control device 100 proceeds from step S4 to step S5. In step S5, control device 100 determines whether or not the current hot water flow rate is lower than the recorded minimum hot water flow rate after the hot water flow rate detected by hot water flow rate sensor 49 has stabilized for a certain time or longer. When the current hot water supply flow rate is equal to or greater than the recorded minimum hot water supply flow rate, control device 100 proceeds from step S5 to return, and ends the routine. When the current hot water supply flow rate is lower than the recorded minimum hot water supply flow rate, control device 100 proceeds from step S5 to step S6. In step S6, the recording unit 104 of the control device 100 records the current hot water supply flow rate as a new minimum hot water supply flow rate instead of the recorded minimum hot water supply flow rate. In this way, the recording unit 104 updates the record of the minimum hot water supply flow rate. Note that, even when there is no recorded value of the minimum hot water supply flow rate, the control device 100 proceeds from step S5 to step S6 and records the current hot water supply flow rate as the minimum hot water supply flow rate.

  The control device 100 proceeds from step S6 to step S7. In step S7, the heat storage temperature control unit 103 of the control device 100 applies the value of the minimum hot water supply flow rate updated in step S6 to the relationship between the heat exchange loss value and the hot water supply flow rate stored in the storage unit 102. Obtain the heat exchange loss value. In the next heat storage operation, the heat storage temperature control unit 103 controls the temperature of the heat storage fluid stored in the hot water storage tank 8 based on the temperature obtained by adding the heat exchange loss value to the hot water supply target temperature.

  According to the present embodiment, the heat exchange loss value is determined according to the actual minimum hot water supply flow rate in the past hot water supply operation, and the temperature of the heat storage fluid stored in the hot water storage tank 8 can be controlled using the heat exchange loss value. If it is this Embodiment, according to the actual condition of a user's use condition, the heat exchange loss value which the thermal storage temperature control part 103 uses can be determined. If it is this Embodiment, since it can suppress reliably that an actual hot water supply temperature becomes higher than hot water supply target temperature, it can suppress reliably that a user's discomfort becomes large. If it is this Embodiment, it can avoid setting the heat exchange loss value which the thermal storage temperature control part 103 uses to a value lower than necessary with respect to the actual condition of a user's use condition. If it is this Embodiment, the heat exchange loss value which the thermal storage temperature control part 103 uses can be set to a more suitable value. Therefore, the temperature of the heat storage fluid stored in the hot water storage tank 8 can be controlled to a more appropriate temperature according to the actual state of use of the user. Therefore, the actual hot water supply temperature can be brought closer to the hot water supply target temperature.

  Note that the recording unit 104 may limit the period for recording the value of the minimum hot water supply flow rate to a certain period (for example, two weeks). That is, the recording unit 104 may delete the record of the minimum hot water supply flow rate older than the past fixed period (for example, the past two weeks) and replace it with the record of the minimum hot water supply flow rate within the past fixed period. By doing in this way, it can respond appropriately also when the actual condition of a user's use condition changes with progress of a month and day.

DESCRIPTION OF SYMBOLS 1 Compressor 3 Water-refrigerant heat exchanger 4 Expansion valve 5 Refrigerant pipe 6 Evaporator 7 HP unit 8 Hot water storage tank 8a Water inlet 8b Water outlet 8c Hot water inlet 8d Hot water inlet 8e Hot water outlet, 8f Hot water inlet, 9a First water pipe, 9b Second water pipe, 9c Third water pipe, 9d Water pipe, 10 Water outlet pipe, 12 Water pump, 13 Hot water pipe, 14 HP Outward pipe, 15 HP return pipe, 16 Bypass pipe, 17 Heating temperature sensor, 18 Three-way valve, 21 Hot water supply pipe, 31 Pressure reducing valve, 33 Tank unit, 34 Hot water tap, 35 Hot water supply machine, 42, 43 Hot water storage temperature sensor, 44 Remote control 46 heat source circuit, 46a heat source introduction pipe, 46b heat source outlet pipe, 48 fluid pump, 49 hot water flow rate sensor, 50 heat source side The amount sensor, 51 water mixing, heat exchanger 52 hot water, 53 hot water pipe, 100 controller, 101 pump control unit, 102 storage unit, 103 heat storage temperature control unit, 104 recording unit, 1000 processor, 1001 Memory

Claims (4)

A heat storage tank for storing a heat storage fluid;
Heating means for heating the heat storage fluid;
A hot water supply heat exchanger that heats the water supply by exchanging heat between the heat storage fluid supplied from the heat storage tank and water supply supplied from a water source;
A fluid pump for supplying the heat storage fluid to the hot water heat exchanger;
A hot water flow sensor for detecting the flow rate of the water supply;
Pump control means for controlling the fluid pump so that the flow rate of the heat storage fluid supplied to the hot water heat exchanger matches a target flow rate determined according to the flow rate of the water supply;
Storage means for storing information on a heat exchange loss value that is a difference between the temperature of the heat storage fluid supplied to the hot water supply heat exchanger and the temperature of the water supply flowing out of the hot water supply heat exchanger;
A heat storage temperature control means for controlling the temperature of the heat storage fluid stored in the heat storage tank, based on a temperature obtained by adding the heat exchange loss value to a target temperature of the water supply flowing out of the hot water heat exchanger;
A water heater equipped with.   The hot water supply apparatus according to claim 1, wherein the storage unit stores the heat exchange loss value when the flow rate of the water supply becomes an assumed minimum flow rate.   The hot water heater according to claim 1, wherein the storage unit stores a relationship between a flow rate of the water supply and the heat exchange loss value. Based on information detected by the hot water flow rate sensor, the recording means for recording the minimum flow rate of the flow rate of the water supply when the flow rate of the water supply is stable,
The heat storage temperature control means adds the heat exchange loss value obtained based on the minimum flow rate recorded by the recording means and the relationship to a target temperature of the water supply flowing out from the hot water supply heat exchanger. The water heater according to claim 3, wherein the temperature of the heat storage fluid stored in the heat storage tank is controlled based on the temperature.

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